2-Aminothiazole → 7-Methyl-5H-(1,3)thiazolo(3,2-a)pyrimidin-5-one

To a stirred solution of 2-aminothiazole (5 g, 49.931 mmol) in acetic acid (40 ml) was added ethyl acetoacetate (9.48 ml, 74.843 mmol) at room temperature. The reaction mixture was heated to reflux for 12 h under nitrogen. The reaction mixture was cooled to room temperature. The residue obtained after concentration under reduced pressure was basified with saturated NaHCO3 solution and diluted with ethyl acetate (50 ml). The organic layer was washed with brine (100 ml), dried (Na2SO4) and concentrated to afford a crude product which was purified by silica gel column chromatography using 1% methanol in chloroform to give 3.3 g of the product as a white solid; 1H NMR (300 MHz, CDCl3) δ 2.38 (s, 3H), 6.15 (s, 1H), 6.95 (d, J=4.8 Hz, 1H), 7.94 (d, J=4.8 Hz, 1H).

1. temperatureThe reaction mixture was heated
2. temperatureto reflux for 12 h under nitrogen
3. customThe residue obtained
4. concentrationafter concentration under reduced pressure
5. additiondiluted with ethyl acetate (50 ml)
6. washThe organic layer was washed with brine (100 ml)
7. dry with materialdried (Na2SO4)
8. concentrationconcentrated
9. customto afford a crude product which
10. customwas purified by silica gel column chromatography

ORD record

ord-8dd4d205423a43478a9ccaa05b2abda0

Source dataset

uspto-grants-2013_08

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08518955B2